1. Field of the Invention
This invention relates to a disc cartridge, and more particularly to a disc cartridge wherein a disc-like medium such as a magnetic disc, a floppy disc, a hard disc, a cleaning disc, an optical disc, a magneto-optical disc or the like is rotatably received in a casing.
2. Description of the Prior Art
Conventionally, a disc cartridge is generally constructed in such a manner that a disc-like medium such as a floppy disc, a compact disc, a video disc or the like which is used for a digital data storing unit, a video equipment unit or the like is rotatably received in a casing to prevent adhesion of dust thereto and damage thereto. Also, the conventional disc cartridge, as shown in FIG. 1, is so constructed that the casing is provided on an inner surface thereof with an elastic lifter means 102 so as to exhibit an elastic force in a predetermined direction to pressedly contact sheet-like liners with the disc. In FIG. 1, the casing is designated by reference numeral 100.
In the conventional disc cartridge thus constructed, the lifter means 102 is formed and provided separate or independent from the casing 100. For example, the lifter means is formed by bending a part of a metal plate at a mounting portion of the inner surface of the casing or made of a film of a synthetic resin material such as PET (polyethylene terephthalate) or the like. The metal plate is fixed on the casing by caulking, while the PET film is fixed to the casing using a fixing means 104 such as a double-coated adhesive tape or the like.
Thus, the casing 100 and lifter means 102 are formed separate from each other, to thereby increase the number of parts of the disc cartridge and render assembling of the disc cartridge troublesome. Also, caulking or using of the fixing means 104 causes productivity of the disc cartridge to be highly deteriorated to incur an increase in manufacturing cost. Further, use of a metal plate for the lifter means of which a distal end exerts pressure on the disc leads to damage to the disc, in particularly, due to any possible burr produced on the metal plate, to thereby fail to provide the disc cartridge with satisfactory durability and reliability; whereas use of a synthetic resin such as PET for the lifter means leads to creep deformation of the lifter means sufficient to significantly decrease the pressing force of the lifter means acting on the disc, resulting in the disc being deformed.